The goals of this project are to establish the primary structure of the human skeletal muscle thin filament proteins tropomyosin, troponin complex and actin, ascertain their molecular heterogeneity and correlate some aspects of their structures and functions. This data will serve as a frame of reference for comparison with proteins obtained from normal fetal tissues and those from individuals who have died of muscular diseases with the aim of assessing the normal developmental course for these molecules and their possible implication in pathological processes.